#include <stdio.h>
#include <math.h>
#define PI  3.14159265358979323846
double divjiecheng(int n)
{double x = 1;
    for (; n > 0; n--)
    {
        x = x * 1.0 / n;
    }return x;
}
double mycos(double x)
{double a = 0;
    int sign;
    if(x > 0) sign = 1;
    if(x < 0) sign = -1;x = fabs(x);
    while(x > 2.0 * PI)
    {
        x = x - 2.0 * PI;
    } 
    x = x * sign;
    for (int n = 0; n < 10; n++)
    {
        a = a + pow(-1, n) * pow(x, 2 * n) * divjiecheng(2 * n);
    }
    return a;
}
int main(int argc, char const *argv[])
{
    double x = PI / 4.0;
    printf(" mycos:%.6lf\nsystem:%.6lf\n", mycos(x), cos(x));
    return 0;
}
#include <stdio.h>

int main( int argc, const char * argv[] )
{
	int c;
	while ( 1 )
	{
		c = getchar();
		if ( c == EOF )
		{
			perror( "getchar()" );
			return(-1);
		}
		putchar( c );
	}

	return(0);
}


